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Energy and exergy analysis of a novel collector design in a photovoltaic thermal system: An experimental study

2024; Elsevier BV; Volume: 256; Linguagem: Inglês

10.1016/j.applthermaleng.2024.124125

1873-5606

Hariam Luqman Azeez, Adnan Ibrahim, Banw Omer Ahmed, Ali H.A. Al‐Waeli, Mahmoud Jaber, Muhammad Aqil Afham Rahmat,

Solar Radiation and Photovoltaics

Photovoltaic Thermal Collectors are designed specifically to overcome the efficiency limitations found in standalone photovoltaic systems. Despite their potential benefits, existing literature consistently highlights the low thermal efficiency challenges associated with collector designs in photovoltaic thermal systems. In response to these efficiency hurdles, this study aims to showcase the energy and exergy effectiveness of an innovative collector design. The design includes an absorber tube featuring a dimpled and petaled array surface and equipped with a coiled twisted tape, enclosed in a 1 % volume concentration of silicon carbide (SiC) nanophase change material and channeling SiC based nanofluids at 0.3 % and 0.6 % volume concentrations. The study employs an indoor solar simulator to investigate how various parameters influence the energy and exergy performance of the system. The parameters include mass flow rates of (0.01, 0.025, 0.04, 0.055, 0.07, and 0.085) kg/s, solar irradiances of (400, 600, 800, and 1000) W/m2, and different coolant types such as water, 0.3 % SiC, 0.6 % SiC, water with nanophase changing material, 0.3 % SiC with nanophase changing material, and 0.6 % SiC with nanophase changing material. The findings reveal a direct correlation between mass flow rates and electrical energy efficiency, thermal energy efficiency, and electrical exergy efficiency. However, increasing mass flow rates negatively impacts thermal exergy efficiency. Additionally, higher solar irradiances enhance both energy and exergy performance up to 1000 W/m2, beyond which a decline is observed. Effective cooling techniques significantly improve overall energy and exergy efficiencies, with peak electrical energy and thermal energy efficiencies reaching 11.7 % and 87.7 %, respectively. Moreover, the highest electrical exergy efficiency and total exergy efficiency recorded are 11.8 % and 15.7 %, respectively. Notably, employing 0.6 % SiC with nanophase changing material as the cooling technique proves most effective, achieving a maximum power output of 27.14 W.